Platform device and method of use to assist in anastomosis formation

ABSTRACT

There is described a platform device for use in forming an anastomosis and maintaining a desired curvature of a lumen in a desired shape during an anastomosis assistance period. The platform is formed from one or more bioabsorbable or biodegradable polymer filaments. There is also described a method for inserting a platform device for use in creation of an arteriovenous fistula by identifying a candidate artery and a candidate vein and dissecting the candidate vein. Next, inserting a platform device into the vein and creating a breach in the candidate artery at a desired angle and location. Next, introducing the platform device and vein into the candidate artery and forming the platform device into a curvature angle selected to minimize turbulent blood flow in an anastomosis formed by the vein and the artery. The platform may also be used to maintain potency of supply blood vessels and/or organ blood vessels or the lumens during an organ transplant procedure.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. 119 of U.S.Provisional Patent Application No. 61/917,081, filed Dec. 17, 2013,titled “DEVICE TO ASSIST IN ARTERIOVENOUS FISTULA FORMATION” and U.S.Provisional Patent Application No. 62/032,818, filed Aug. 4, 2014,titled “IMPROVED DEVICE TO ASSIST IN FISTULA FORMATION,” each of whichis herein incorporated by reference in its entirety.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

None.

FIELD

The present invention relates to medical devices used to assist medicalpersonnel in vascular access procedures, particularly those proceduresinvolving the creation of an anastomosis platform device embodiments ofthe present invention include a structure to support a vessel during andafter surgical intervention. Specifically, one embodiment of theplatform device structure supports the joining of blood vessels, like inthe formation of an anastomosis, or an arteriovenous fistula.

BACKGROUND

Nearly 2.5 million patients worldwide suffer from End Stage RenalDisease (ESRD). To treat ESRD, patients are either subjected to a kidneytransplant or undergo hemodialysis. Though acting as artificial kidneys,dialysis machines are not implanted in the body; instead, they requiredurable external access points to the body's circulatory system, oftenin the form of an arteriovenous fistula (AVF). An AVF is created via anartificial junction, or “anastomosis”, between an artery and a veinwhich is used to increase the volume of blood flow through the vein.Over time, the increase in blood flow volume increases the size of thevein.

As the circulatory system is typically understood, blood flows away fromthe heart through a series of arteries. Arteries branch off to evensmaller vessels called capillaries, where nutrients such as oxygen aredelivered to muscle tissues and cells. Thereafter, deoxygenated bloodcontinues to flow through capillaries, and eventually returns to largervessels called veins. Veins carry deoxygenated blood back to the heartand lungs, where the blood is reoxygenated and continues through thecirculatory system.

In order to create an arteriovenous fistula, this process isshort-circuited. There are a number of locations within the body wherean arteriovenous fistula may be created, but for hemodialysis patientsthe most common location is on the non-dominant forearm. In order tocreate the fistula, the patient is generally put under anesthesia and asmall incision is made to open up the patient's forearm in order toexpose a superficial vein. The cephalic vein is tied off from blood flowand subsequently severed. The proximal (that is, the segment of thecephalic vein which maintains blood flow to the heart) is then sutureddirectly to the nearby radial artery and blood flow through the vein isresumed.

Because the normal capillary diffusion system is eliminated, blood flowthrough the cephalic vein is increased beyond what the vessel isaccustomed to. In order to accommodate the increased blood flow, thesize of the cephalic vein begins to expand over a period of weeks untilthe vein itself begins to bulge from under the skin of the patient, aprocess called AVF maturation. When the bulging vein has reachedsufficient size, medical personnel implant dialysis needles into thevein such that dialysis machines can be connected to the patient'scirculatory system.

The best hemodialysis vascular access is an Arteriovenous Fistula (AVF).In order to create an AVF, it is required to connect an artery with avein. After the surgery 6-8 weeks are needed for fistula maturation.During the maturation the venous segment of the fistula is growing. Thegrowing of the vein is triggered by the increased blood flow through thevein. The laminar flow of the blood through the fistula is responsibleto initiate a cascade of events leading the fistula vein growth andfistula maturation. Conversely a turbulent blood flow will stimulate thevein to stenose preventing the fistula from maturing.

Unfortunately, there are a number of complications that may occur in thecreation of an arteriovenous fistula. For example, the typical AVFrequires 6-8 weeks to mature to a size and strength sufficient tosupport insertion of a dialysis needle. Further, 45-55% of AVFs fail tosufficiently mature, requiring the creation of a new arteriovenousanastomosis and a further 6-8 weeks of maturation time before a newfistula is created.

Many of the AVF created do not mature to a usable AVF. In US, the AVFmaturation rate ranges between 45-55%. Most of the times the cause ofnonmaturation is the presence of perianastomotic stenosis (narrowing ofthe vessel in the area of the surgical anastomosis) found to be presentin 75% of nonmaturing AVF. The trauma of the surgery and the turbulentblood flow are believed to be responsible for the development ofperianastomotic stenosis. The turbulent flow involved in the lack offistula maturation might be created by the steep angle the vein isanastomosed to the artery. FIG. 1A illustrates a vein 31 formed into acurvature 23 attached to an artery 32. The attached vein 31 forms asteep anastomosis angle 36 approaching 90 degrees. FIG. 1B illustratesthe degraded situation of the anastomosis of FIG. 1A after a few weeks.FIG. 1B illustrates a partially matured arteriovenous anastomosis Dformed by an artery A and a vein C. There is a panastomosis B formed inthe vein C. Note as well the steep angle 36 of the anastomosis D.

AVF developmental complications are generally attributed to increases inblood flow shear stress, i.e. turbulence, created due to the artificialnature of the arteriovenous anastomosis. As the blood flows through theartery and into the vein, it has been observed to eddy, or pool, insteadof flowing smoothly through the anastomosis. This turbulent flow causesblood vessel stenosis—a narrowing of the vessel which limits theavailable flow rate. As stenosis occurs in the fistula anastomosis, thevolume of blood flow is reduced, and the vessel may fail to stretch tothe volume required to support a dialysis access port. It is thereforedesirable to design a device which minimizes the amount of turbulentblood flow through the AVF anastomosis.

SUMMARY OF THE DISCLOSURE

In general, in one embodiment, a platform device includes abioabsorbable filament selected to begin degrading within one week ofimplantation into a lumen of a human or animal body and to besubstantially completely absorbed by the animal or human body after ananastomosis assistance period has elapsed; and a coil structure having alength along a major axis and a width along a minor axis formed by aplurality of windings of the filament about the major axis wherein thefilament width and the spacing between windings relates to the coilstructure length and the dimension of the windings across the minor axisrelates to the coil structure width.

This and other embodiments can include one or more of the followingfeatures. In one aspect, the anastomosis assistance period can be lessthan three weeks. In another aspect, the anastomosis assistance periodcan be less than five weeks. In a further aspect, when the coilstructure is in a stowed configuration the plurality of windings canprovide an overall cylindrical shape to the coil structure. In analternative aspect, when the coil structure is in a deployedconfiguration the spacing between adjacent windings can be differentthat the spacing between adjacent windings in the stowed configuration.In yet another aspect, when the coil structure is in a deployedconfiguration the coil structure can form a selected anastomosis anglehaving an inner radius of curvature and an outer radius of curvaturewherein the spacing between adjacent windings along the inner radius ofcurvature can be less than the spacing between adjacent windings alongthe outer radius of curvature. In still another aspect, a distalaperture of the platform can be formed into an oblong or ovoid shapeprior to forming an anastomosis. In one aspect, a distal aperture of theplatform can be formed into a shape selected based on a dimension or ashape of another lumen at an anastomosis site. In another aspect, thebioabsorbable filament can be a biocompatible polymer selected from thegroup consisting of: a (poly)lactic acid, a poly(lactic-co-glycolicacid), a polyglycolide, a copolymer, and a cross-linked polymer. In afurther aspect, the bioabsorbable filament can be a biocompatiblepolymer having an in vivo degradation rate corresponding to ananastomosis assistance period that can correspond to the time requiredfor fistula formation. In an alternative aspect, when the platformdevice is in a deployed configuration a distal aperture of the platformdevice can have one or more windings of decreasing dimension across theminor axis. In yet another aspect, when the platform device is in adeployed configuration one or more windings of the proximal portion ofthe coil structure can form a non-circular opening. In still anotheraspect, the distal aperture can have a circumference and a shapeselected based on an anastomosis angle of the platform device in use toform an arteriovenous fistula. In one aspect, when the platform deviceis in a deployed configuration shaped into a curvature angle for use toform a fistula, a portion of the curvilinear connectors along an innerradius of the curvature angle can be shorter than a portion of thecurvilinear connectors along an outer radius of the curvature angle. Inanother aspect, when the platform device is in a deployed configurationwithin the lumen to facilitate formation of an arteriovenous fistula,one or more of the windings can be manipulated to provide a provide alumen having a tilted conical trunk and an obtuse curvature angle. In afurther aspect, when the platform device is formed to facilitateformation of an arteriovenous fistula a proximal aperture of theplatform device can have an ovoid or oblong shape. In an alternativeaspect, in use to facilitate formation of an arteriovenous fistula aplurality of distal windings can provide the coil structure with agenerally circular distal portion and a plurality of proximal windingsprovide the coil structure with a generally non-circular proximalopening. In yet another aspect, in use to facilitate formation of anarteriovenous fistula the circumference of a distal portion of the coilstructure within the lumen beyond a dissection location can be less thanthe circumference of a distal portion of the coil structure adjacent toan anastomosis connection location. In still another aspect, theplatform device can further include an obdurator and can have a distalend, a proximal end, and an overall shape adapted to receive theplurality of windings. In one aspect, the obdurator can have a tip onthe distal end and an increasing diameter of the overall shape towardsthe proximal end. In another aspect, the obdurator can include a matingfeature shaped to receive a corresponding mating feature formed on adistal portion of the filament. In a further aspect, the obduratordistal in diameter can be smaller than the obdurator proximal enddiameter. In an alternative aspect, the diameter increase along theobdurator can be gradual. In yet another aspect, the diameter increasecan be a step. In still another aspect, the step can be sized to besmaller than a filament width. In still another aspect, the step can besized to be greater than or about the same as a filament width. In oneaspect, the platform device can further include an introducer sheathhaving a lumen dimensioned to receive the filament loaded onto theobdurator.

In general, in one embodiment, a method for inserting a platform devicefor use in creation of an arteriovenous fistula, including the steps of:identifying a candidate artery and a candidate vein; dissecting thecandidate vein; inserting a platform device into the vein; creating abreach in the candidate artery at a desired angle and location; formingan anastomosis by attaching the vein to the artery; and manipulating theplatform device into a shape selected to minimize turbulent blood flowin the anastomosis.

This and other embodiments can include one or more of the followingfeatures. In one aspect, after the manipulating step the anastomosis canbe formed by the vein and the artery forms an anastomosis angle between90 degrees and 180 degrees. In another aspect, the anastomosis angle canbe between 100 degrees and 130 degrees. In a further aspect, the methodof the forming step can further include suturing the vein to the arterywithout incorporating any of the platform device. In an alternativeaspect, the method of the forming step can further include suturing thevein to the artery so that substantially all of the platform device iswithin the vein. In yet another aspect, the method can further includeexpending an angioplasty balloon to expand the vein before or after theinserting step. In still another aspect, the method can further includeexpending a plurality of coils within the platform during the expandingstep. In one aspect, after the forming step the spacing can be increasedbetween adjacent windings in a first portion of the platform device andthe spacing can be decreased between adjacent windings in a secondportion of the platform device. In another aspect, after the formingstep or the manipulating step a circumference can be formed by aplurality of windings in a proximal portion of the platform deviceattached to the artery can be larger than a circumference formed by aplurality of windings in a distal portion of the platform device withinthe vein. In a further aspect, after the forming step or themanipulating step the distal aperture can be formed by a plurality ofthe distal most windings of the platform device attached to the arteryform an imperfectly circular shape. In an alternative aspect, the veincan be a cephalic vein and the artery can be a radial artery. In yetanother aspect, the method of the forming step can further includeapplying heat to the platform device before, after or during any of thesteps. In still another aspect, the method can further include after theinserting step, tying together a portion of a first filament of theplatform device to a portion of a second filament of the platformdevice. In one aspect, the method can further include after theinserting step, adjusting the size of the platform device by removing aportion of a first filament of the platform device or a second filamentof the platform device. In another aspect, the method can furtherinclude forming a desired anastomosis angle by inserting a shape toolinto the platform device proximal aperture. In a further aspect, theforming step can be performed after the inserting step. In analternative aspect, the method can further include before the insertingstep: loading the platform onto an obdurator and during the insertingstep rotating the obdurator.

In general, in one embodiment, a platform device for coupling one lumento another, including: a biodegradable polymer filament havingproperties selected so as to remain within the one lumen for at leastone week and be substantially absorbed or biodegraded by three weeks;the filament having a cross-section dimension of from about 0.004 inchesto about 0.007 inches; the filament formed into a coil structure of aplurality of windings about a central longitudinal axis a length along acentral longitudinal axis from a proximal end to a distal end.

This and other embodiments can include one or more of the followingfeatures. In one aspect, the filament can have a circular cross-sectionshape, an oval cross-section shape, an elliptical cross-section shape, arounded rectangular cross-section shape, a tear drop cross-sectionshape, or a ellipsoid cross-section shape. In another aspect, thefilament can further include a first portion having a first overallwidth and a first cross-section shape and a second portion having asecond overall width and the second cross-section shape. In a furtheraspect, the first overall filament width can be greater than the secondoverall filament width. In an alternative aspect, the width of the coilstructure can be between 2 mm to 4.5 mm. In yet another aspect, thefirst cross-section shape can be the same as the second cross-sectionshape and the first overall width is greater than the second overallwidth. In still another aspect, the first overall width can be about thesame as the second overall width and the first cross-section shape canbe different than the second cross-section shape. In one aspect, whenthe platform device is in use within a lumen of the body the overalldiameter of the coil structure can increase from the proximal end to thedistal end of the platform device. In another aspect, the overalldiameter can be from about 2 mm to about 6 mm. In a further aspect, whenthe platform device is in use within a lumen of the body the overalldiameter of the coil structure can decrease from the proximal end to thedistal end of the platform device. In an alternative aspect, the overalldiameter can be from about 2 mm to about 6 mm. In yet another aspect, aproximal or distal terminal end of the filament can be modified toreduce a risk of penetration of an adjacent lumen wall while theplatform device can be implanted within the lumen. In still anotheraspect, the proximal or distal terminal end can be bent into a curve,formed into a rounded portion, formed into a bulbous portion, or coveredwith a ball.

In general, in one embodiment, a platform device for coupling one lumento another, including: a first and a second biodegradable polymerfilament having properties selected so as to remain within the one lumenfor at least one week and be substantially absorbed or biodegraded bythree weeks; the first and the second filaments having a cross-sectiondimension of from about 0.002 inches to about 0.007 inches; the firstand the second filaments formed into a pair of adjacent coil structureseach one having a plurality of windings about a common centrallongitudinal axis a length along the common central longitudinal axisfrom a proximal end to a distal end.

This and other embodiments can include one or more of the followingfeatures. In one aspect, the first or the second filament can have acircular cross-section shape, an oval cross-section shape, an ellipticalcross-section shape, a rounded rectangular cross-section shape, a teardrop cross-section shape, or a ellipsoid cross-section shape. In anotheraspect, the first or the second filament can further include a firstportion having a first overall width and a first cross-section shape anda second portion having a second overall width and the secondcross-section shape.

In a further aspect, the first or the second filament having a firstoverall filament width can be greater than the second overall filamentwidth. In an alternative aspect, the first filament can have a crosssection dimension greater than the second filament cross sectiondimension. In yet another aspect, when the platform device can be in usewithin a lumen of the body the overall diameter of the coil structurescan increase from the proximal end to the distal end of the platformdevice. In still another aspect, the overall diameter can be from about2 mm to 6 mm at a distal portion to about 2 mm to 6 mm at a proximalportion. In one aspect, when the platform device can be in use within alumen of the body the overall diameter of the coil structures candecrease from the proximal end to the distal end of the platform device.In another aspect, the overall diameter can be from about 2 mm-4 mm at adistal portion to about 4 mm-6 mm at a proximal portion. In a furtheraspect, a proximal or distal terminal end of the first or the secondfilament can be modified to reduce a risk of penetration of an adjacentlumen wall while the platform device is implanted within the lumen. Inan alternative aspect, the proximal or distal terminal end of a firstfilament or a second filament can be bent into a curve, formed into arounded portion, formed into a bulbous portion, or covered with a ball.In yet another aspect, a portion of the first filament can be tied to aportion of the second filament at a proximal end or a distal end of theplatform device. In still another aspect, a portion of the firstfilament can be tied to a portion of the second filament at the proximalplatform end and at the distal platform end.

In general, in one embodiment, a method of forming an anastomosis with abioabsorbable platform device, comprising: dissecting a portion of alumen within a body to form a proximal fixed lumen portion and a distalunattached lumen portion having an open proximal end; inserting theplatform device into the open proximal end and along the unattachedlumen portion; and positioning a portion of the platform device tomaintain the open proximal end in a configuration selected for couplingthe open proximal end to an anastomosis location.

This and other embodiments can include one or more of the followingfeatures. In one aspect, the method after the inserting step can furtherinclude advancing the platform device within the lumen until a portionof the platform device is within the proximal fixed lumen portion. Inanother aspect, the method can further include after the positioningstep and with the platform device present within the unattached lumenportion, coupling the open lumen end to the anastomosis location. In afurther aspect, after the positioning step, the step of bending an endof the filament in the platform device can be performed. In analternative aspect, after the positioning step, there can be a step oftying together the first filament of the platform device and a secondfilament of the platform device. In yet another aspect, the method canfurther include cutting a portion of the unattached lumen portion toshape the open proximal end for coupling to the anastomosis location. Instill another aspect, after the coupling step the position of a portionof the platform device within the unattached lumen can be adjusted toform a desired angle between the unattached lumen portion and theanastomosis location. In one aspect, the desired angle can be an angleselected to produce a desired flow pattern within the lumen. In anotheraspect, the anastomosis can be formed with a vein and an artery, a bloodvessel and a vessel of a transplant organ. In a further aspect, themethod can further include inserting a platform device into a vein orartery of a transplant organ.

In an alternative aspect, the length from the platform proximal portionto the distal portion can be from about 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7cm, 8 cm, 9 cm, 10 cm, 11 cm or 12 cm before implantation into a lumen.In yet another aspect, the length from the platform proximal portion tothe distal portion can be from about 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm,8 cm, 9 cm, 10 cm, 11 cm or 12 cm after implantation into a lumen.

In any of the above or in still further embodiments, there may beincluded one or more or an advantageous combination of the followingfeatures. In one aspect, there is a tubular body, or a filament formedinto windings of a coiled body or braid or a platform device can beconstructed of a biocompatible polymer selected from the groupconsisting of a (poly)lactic acid (PLA), a polylactic-co-glycolic acid)(PLGA), a polyglycolide (PGA), a copolymer, a poly-1-lactic acid (PLLA)and a cross-linked polymer. In another aspect, the tubular body can beconstructed from a biocompatible polymer having an in vivo degradationrate corresponding to the time required for fistula formation. In stillanother aspect, a filament used in the devices described herein may beconstructed of a biocompatible/bioabsorbable polymer comprising a(poly)lactic acid, a poly(lactic-co-glycolic acid), a polyglycolide, acopolymer, or a cross-linked polymer and optionally includingcopolymerization with lower levels of L-lactide, such as for example90/10 glycolide/L-lactide, 80/20 glycolide/L-lactide so that thefilament is metabolized within 3 weeks, or within 2 weeks, or, within2-3 weeks, or, substantially completely metabolized at or before afistula maturation of a fistula formed using the filament or platformdevice. In still other embodiments, a bioabsorbable polymer filamentcomprises 100% PLGA. In still other embodiments, a bioabsorbable polymerfilament comprises 90/10 PGA/PLLA. In still other embodiments, abioabsorbable polymer filament comprises 90/10 PGA/PLGA. In still otherembodiments, a bioabsorbable polymer filament comprises alactide/glycolide mole ratio of 50/50. In still other embodiments, abioabsorbable polymer filament comprises 50/50 PLLA-PGA. In still otherexemplary embodiments, a tubular body, or a filament formed intowindings of a coiled body or braid or a platform device can beconstructed of a biocompatible, biodegradable polymer comprising a(poly)lactic acid (PLA), or a poly(lactic-co-glycolic acid) (PLGA), or apolyglycolide (PGA), or a copolymer, or a poly-1-lactic acid (PLLA) or across-linked polymer selected to provide initial support at ananastomosis site with a bioabsorption or degradation rate selected tohave the filament or structure formed by the filament substantiallycompletely or sufficiently absorbed or metabolized such that thefilament or structure produced by the filament does not impede the flowof fluids within a lumen that contained the implanted filament basedstructure. In still other alternatives, the filament or platform devicecomprises a hydrolytic, bio-absorbable polymer or co-polymer blend thatis substantially completely absorbed within three weeks of beingimplanted into a human or animal body. In still another alternative, thefilament or platform device comprises a hydrolytic, bio-absorbablepolymer or co-polymer blend that is substantially completely absorbedwithin two to three weeks of being implanted into a human or animalbody. In still other variations of any of the above or in otheralternatives, a filament as used herein may undergo a form of mechanicaldisruption to accelerate polymer hydrolysis.

In one aspect, there is also a platform as described above that includesan anti-inflammatory composition on or within all or a portion of afilament.

In another aspect, there is a platform as described above that includesan anti-proliferative composition on or within all or a portion of afilament.

In yet another aspect, there is a platform as described above thatincludes an anti-thrombotic composition on or within all or a portion ofa filament.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1A is a simplified top view of an arteriovenous anastomosis justafter surgery.

FIG. 1B is a representative view of the arteriovenous anastomosis ofFIG. 1B with a non-maturation complication, a para anastomotic stenosis.

FIG. 2A is a side view of a platform device with small spacing betweenadjacent windings.

FIG. 2B is an isometric view of the platform device of FIG. 2A withincreased spacing between adjacent windings.

FIG. 2C is a side view of the platform of FIG. 2A, to be implantedwithin and shaping a vein use to form an arteriovenous fistula with andartery.

FIG. 2D is a side view of a portion of the platform illustrating how thewindings and coil structure may be modified to alter the lumen.

FIGS. 3A-3E are various alternative configurations of the terminal endof a filament.

FIG. 4A is a platform embodiment having a coiled body formed of a smallfilament with only a few windings.

FIG. 4B is a platform embodiment having a coiled body formed by a largerfilament with a large number of small windings.

FIG. 5 is a side view of the platform device embodiment having aproximal portion with a larger diameter than a distal portion.

FIG. 6A is a cross-section view of the filament with a roundcross-section shape.

FIG. 6B is a cross-section view of the filament with a generallyrectangular cross-section shape.

FIG. 6C is a cross-section view of a filament with a rounded rectangularcross section shape.

FIG. 6D is a cross-section view of the filament having a rounded shapeand at least one flat side.

FIGS. 7A and 7B are side views of the platform device having a filamentwith a generally rectangular cross-section shape in a stowed or compactconfiguration (FIG. 7A) and a deployed or expanded configuration (FIG.7B).

FIG. 8A is a section view of an embodiment of a three strand filament.

FIG. 8B is a section view of a four strand filament.

FIG. 9A is a cross-section view of a three rounded cross-sectionfilaments of a platform device in contact with a section of a lumenwall.

FIG. 9B is a cross-section view of a three rounded cross-section,multiple layer or composite filaments of the platform device in contactwith a section of a lumen wall.

FIG. 9C is a cross-section view of a three rectangular or ribbon shapedcross-section filaments of the platform device in contact with a sectionof a lumen wall.

FIG. 9D is a cross-section view of three braided filaments of a platformdevice in contact with a section of a lumen wall.

FIG. 10A is a side view of the dual filament platform device.

FIG. 10B is a side view of a section of a dual filament platform device.

FIG. 10C is a side view of a section of a dual filament platform device.

FIG. 11A is a cross-section view of an obdurator loaded with a platformdevice having a filament with different diameter along the length andloaded with fairly even spacing on the obdurator.

FIG. 11B is a cross-section view of an obdurator loaded with a platformdevice having a filament width rounded, flat and smaller roundedcross-section shapes.

FIG. 11C is a cross-section view of an obdurator loaded with a filamenthaving a flat, smaller rounded and larger rounded cross-section shape.

FIG. 11D is a cross-section view of an obdurator loaded with a filamenthaving a smaller rounded and then larger rounded cross-section shapesloaded with a smaller spacing on the distal portion and increasingspacing in a proximal portion.

FIGS. 12A and 12B are top and side views respectively of an obduratorhaving a receiver for a filament to secure a platform onto theobdurator.

FIG. 12C is a side view of the obdurator of FIGS. 12A, 12B with aplatform device loaded onto and secured to the obdurator.

FIG. 12D is a partial section view of the loaded obdurator of FIG. 12Cbeing rotated into a lumen for the deployment of the platform.

FIG. 12E is a side view of an obdurator having an increasing diameterfrom the proximal end to the distal end.

FIG. 13 is a cross-section view of the platform device loaded onto thereduced diameter distal end of an obdurator disposed within a deliverysheath.

FIG. 14 is a cross-section view of the platform device loaded onto anobdurator with a delivery sheath that covers the distal portion of theplatform device.

FIGS. 15A-15D illustrate, respectively, the initial (FIG. 15A) anddegrading (FIG. 15B, 15C) conditions of a platform device that isfinally absorbed completely (FIG. 15D).

FIGS. 16A-16G illustrate a representative surgical procedure for the useof a platform device based anastomosis formation.

FIG. 17 is a flowchart of an exemplary platform device based method ofanastomosis formation.

FIGS. 18A1-18G are various views of a platform and insertion deviceduring the steps of the method of FIG. 17.

FIG. 19 is a top section view of a transplanted organ illustrating theuse of various platform embodiments to enable a platform device assistedrevascularization procedure where various platforms are used to open andsupport lumens as well as provide for shaping of vessels to be attachedto the organ.

FIG. 20 is a cross-section view of an obdurator with different finalplatform diameters relative to an exemplary lumen diameter.

DETAILED DESCRIPTION

In one embodiment of the present invention, a platform device 10 used tosupport the formation of an anastomosis is provided. The platform device10 may be composed of a filament of a polymeric material selected from anumber of biodegradable compounds which are identified based on their invivo degradation rate, biocompatibility, malleability, or other relevantcharacteristics. The body of the device 10 may further be formed from aseries of coils 14 of a biodegradable compound. The device 10 mayfurther be formed with concentric coils, producing a narrow distal endand a wider proximal end (see e.g., FIGS. 2D and 5).

In another embodiment of the present invention, the device is shaped toform a conical trunk, wherein the aperture of the device at theanastomosis has a greater circumference than the remaining portion ofthe device.

In yet another embodiment of the present invention, the device may bebent or curved such that it adopts an angle of anastomosis whichpromotes laminar, non-turbulent, blood flow through the arteriovenousinterface. The curve may not be formed into the device at production,but the device may be made of materials selected so that the operatorcan form it to a curve of her choosing during surgical procedure. Forexample, the device 10 can be formed of a material that is malleable ata low temperature but a temperature warmer than body temperature.

In general, in one embodiment of a platform device 10 the presentinvention configured for use with an arteriovenous fistula, device 10includes a generally tubular body formed from loops or windings 16 thatform the tubular or coil structure 14 body. In one embodiment, the loopsare formed from a single filament of biodegradable material as describedabove. At both the proximal and distal ends of the filament, appropriatemodifications are present in order to prevent the filament frompenetrating the wall of the blood vessel. For example, the tip of thefilament is formed to be a ball with a circumference larger than thegauge of the filament (see FIGS. 3A-3E).

This and other embodiments can include one or more of the followingfeatures. For example, a tubular body, or a filament formed intowindings of a coiled body or braid or a platform device can beconstructed of a biocompatible polymer selected from the groupconsisting of a (poly)lactic acid (PLA), a poly(lactic-co-glycolic acid)(PLGA), a polyglycolide (PGA), a copolymer, a poly-1-lactic acid (PLLA)and a cross-linked polymer. In another aspect, the tubular body can beconstructed from a biocompatible polymer having an in vivo degradationrate corresponding to the time required for fistula formation. In stillanother aspect, a filament used in the devices described herein may beconstructed of a biocompatible/bioabsorbable polymer comprising a(poly)lactic acid, a poly(lactic-co-glycolic acid), a polyglycolide, acopolymer, or a cross-linked polymer and optionally includingcopolymerization with lower levels of L-lactide, such as for example90/10 glycolide/L-lactide, 80/20 glycolide/L-lactide so that thefilament is metabolized within 3 weeks, or within 2 weeks, or, within2-3 weeks, or, substantially completely metabolized at or before afistula maturation of a fistula formed using the filament or platformdevice. In still other embodiments, a bioabsorbable polymer filamentcomprises 100% PLGA. In still other embodiments, a bioabsorbable polymerfilament comprises 90/10 PGA/PLLA. In still other embodiments, abioabsorbable polymer filament comprises 90/10 PGA/PLGA. In still otherembodiments, a bioabsorbable polymer filament comprises alactide/glycolide mole ratio of 50/50. In still other embodiments, abioabsorbable polymer filament comprises 50/50 PLLA-PGA. In still otherexemplary embodiments, a tubular body, or a filament formed intowindings of a coiled body or braid or a platform device can beconstructed of a biocompatible, biodegradable polymer comprising a(poly)lactic acid (PLA), or a poly(lactic-co-glycolic acid) (PLGA), or apolyglycolide (PGA), or a copolymer, or a poly-1-lactic acid (PLLA) or across-linked polymer selected to provide initial support at ananastomosis site with a bioabsorption or degradation rate selected tohave the filament or structure formed by the filament substantiallycompletely or sufficiently absorbed or metabolized such that thefilament or structure produced by the filament does not impede the flowof fluids within a lumen that contained the implanted filament basedstructure. In still other alternatives, the filament or platform devicecomprises a hydrolytic, bio-absorbable polymer or co-polymer blend thatis substantially completely absorbed within three weeks of beingimplanted into a human or animal body. In still another alternative, thefilament or platform device comprises a hydrolytic, bio-absorbablepolymer or co-polymer blend that is substantially completely absorbedwithin two to three weeks of being implanted into a human or animalbody. In still other variations of any of the above or in otheralternatives, a filament as used herein may undergo a form of mechanicaldisruption to accelerate polymer hydrolysis.

In another aspect, the distal aperture can have a circumference and ashape selected based on an anastomosis angle of the device in use toform an arteriovenous fistula. In still another aspect, when the deviceis in a deployed configuration shaped into a curvature angle for use toform a fistula, a portion of the curvilinear connectors along an innerradius of the curvature angle can be shorter than a portion of thecurvilinear connectors along an outer radius of the curvature angle. Ina further aspect, when the device is formed to facilitate formation ofan arteriovenous fistula the device has a tilted conical trunk and anobtuse curvature angle. In yet another aspect, when the device is formedto facilitate formation of an arteriovenous fistula a distal aperture ofthe device can have an ovoid or oblong shape. In a further aspect, inuse to facilitate formation of an arteriovenous fistula, there can be acircular opening on the proximal end of the tubular body and anon-circular opening on the distal end of the tubular body. In yet afurther aspect, in use to facilitate formation of an arteriovenousfistula, the circumference of a proximal end of the tubular body can beless than the circumference of a distal end of the tubular body.

In general, in one embodiment, a method for inserting a device for usein creation of an arteriovenous fistula, includes the steps ofidentifying a candidate artery and a candidate vein, dissecting thecandidate vein, inserting a device into the vein, creating a breach inthe candidate artery at a desired angle and location, introducing thedevice and vein into the candidate artery, forming the device into acurvature angle selected to minimize turbulent blood flow in ananastomosis formed by the vein and the artery and fastening a distalportion of the device to the artery to form an anastomosis. The step offastening the distal portion of the device to the vein to form ananastomosis can optionally include the threading distal end of thedevice into the vein, turning the device to engage the filament loopsthat comprise the tubular body into the blood vessel so that the devicedrives into the blood vessel and then securing the proximal end into theartery as described above.

This and other embodiments can include one or more of the followingfeatures. In one aspect, after the fastening step the anastomosis formedby the vein and the artery forms an anastomosis angle between 90 degreesand 180 degrees. In another aspect, the anastomosis angle can be between100 degrees and 130 degrees. In yet another aspect, the fastening stepcan further include engaging a fastener on the distal portion of thedevice with a portion of the artery. In still another aspect, thefastening step can further include suturing the distal portion of thedevice to the artery. In another aspect, the method can further includeusing an angioplasty balloon to expand the vein before or after theinserting step.

In a further aspect, after the forming step or the fastening step acircumference of the proximal aperture of the device attached adjacentto the artery can be larger than a circumference of the distal apertureof the device within the distal vein. In another aspect, after theforming step or the fastening step the proximal aperture of the deviceattached to the artery can be configured into an imperfectly circularshape. In a further aspect, the proximal end of driven device that restsinside the dissected vein, is attached to the artery so that the tensionof the vein and the support of the device maintains a natural angle forthe anastomosis by means of tension: like stringing a bow.

In yet another embodiment, the device is placed into the vein by meansof an introducer. The introducer or obdurator is a small cannula formedto fit the selected vein to dissect. In one embodiment, the introducer(or obdurator) is formed to receive the distal end of the filament andkeep in contact when rotated in a direction to drive the device into thevein or other blood vessel. Still further, the vein can be a cephalicvein and the artery can be a radial artery. In another aspect, theforming step can further include applying heat to the device. In yetanother aspect, the method can further include applying pressure to thedevice. In still another aspect, the forming step can be performed byinserting and inflating a balloon inserted into the device. In anotheraspect, the method can further include forming the desired anastomosisangle by inserting a shape tool into the device proximal aperture afterinsertion into the vessel.

In one embodiment there is provided a platform device for use in thecreation of an arteriovenous fistula. The platform device includes agenerally cylindrical device of a plurality of windings, which may bedeformed to assume a desired curvature, wherein said platform isconfigured for attachment to an artery at its proximal aperture and forinsertion into a vein at its distal aperture. In still otheralternatives, the proximal aperture is connected to the desired arteryat an angle selected to minimize turbulent blood flow in thearteriovenous anastomosis, the angle is between 90 and 180 degrees. Inanother aspect, the tube or platform device may assume a generallyconical shape, where the circumference of the distal aperture is lessthan the circumference of the proximal aperture and, in one embodiment,the desired curvature is achieved by subjecting the coil structure to anexternal stimulus.

In still another aspect, there is provided a method for inserting adevice for use in creation of an arteriovenous fistula. The methodincludes identifying a candidate artery and a candidate vein; dissectingthe candidate vein; using an angioplasty balloon to expand the vein;inserting a device into the vein; creating a breach in the candidateartery at a desired angle and location; introducing the device and veininto the candidate artery; and fastening the vein to the artery. In onealternative, the device's configuration is modified by the applicationof an external stimulus prior to insertion into the candidate artery.These and other details of various embodiments are provided inInternational Patent Application No. PCT/US13/046370 which is hereinincorporated by reference in its entirety.

FIG. 2A is a side view of a platform device 10 having a plurality ofwindings 16 to form a coil structure 14. The platform device 10 has aproximal end 22 and a distal end 24 is formed from a filament 12. Asused herein, a filament of resorbable material having overall dimensions(depending on cross section shape f_(d)) ranges from about 0.002-0.003inches; or 0.002-0.005 inches; or from about 0.004-0.007 inches or fromabout 0.004-0.018 inches. In some braided filament embodiments (seeFIGS. 8A and 8B below) the overall braid would have these exemplarydimensions and individual filament strands making the braid would besmaller. In general and depending upon the desired configuration, afilament 12 is cut to a desired length of from about 1 inch to about 10inches or longer as determined by platform characteristics andanastomosis requirements. Additionally, the filament embodimentsdescribed herein may be constructed of different compositions ofpolylactic acid and different additives to add strength and to controlthe rate of resorption.

Returning to platform 10 shown in FIG. 2A, the filament 12 is formedabout a major axis 2 to form the plurality of windings 16. The windings16 are spaced apart from each adjacent winding by a spacing 6. Eachwinding has a width (D) that is described spanning across a minor axis 4(i.e., across the major axis 2) of the coil structure length (L). Thediameter of the windings may vary depending upon the application of theplatform device. Exemplary windings may be from 2 mm to 10 mm. In someaspects, the platform device will have a winding width during use offrom 2.5 mm to 4 mm, or, optionally, from 4 mm to 6 mm. The width of thewindings may be increased by expanding the windings when implantedwithin a lumen. In the illustrated embodiment of FIG. 2A the filament 12has a generally round cross-section and the terminal ends 18 of thefilament are shown with a flat end 18. In one aspect, the illustratedembodiment of FIG. 2A shows a spacing 6 between each of the adjacentwindings 16 that is small or a compact spacing. A small or compactspacing 6 between windings may be used advantageously when the platformis loaded onto a delivery device and prior to insertion into a lumen.The length of a platform device may be of any length suited to theapplication within the lumen. The length may also be adjusted afterimplantation by adjusting the spacing 6 between windings or by alteringthe orientation of the windings (see, for example, FIG. 2D).

As shown in FIG. 2B, the platform 10 illustrated has increased spacing 6between adjacent windings 16. Increased spacing 6 between adjacentwindings will increase the overall length of the coil structure 14. FIG.2C is illustrates a platform 10 (expanded as shown in FIG. 2B) inposition within a vein 31 that has been attached to an artery 32. Theplatform proximal end 22 is used to hold open the vein 31. Adjusting thefilament and/or windings also allows the shape of angle of attachment tobe adapted by the surgeon. The illustrated implementation of a platform10 within a vein 31 as shown in FIG. 2C is illustrative of the use ofthe platform for the formation of a hemodynamic environment conducive toAV arteriovenous fistula maturation.

FIG. 2D is an exemplary section view of one or more windings of theembodiment of FIG. 2C. FIG. 2D illustrates how the windings 16 withinthe platform may be adjusted into different spacing, overall windingshape to facilitate the formation of a desired luminal structure,orientation or shape to facilitate the desired anastomosis environment.Section I illustrates a spacing 6 that is even between adjacent windings16. Section II illustrates a spacing 6 that varies between adjacentwinding s 16. Section III illustrates how spacing 6 and the anglebetween adjacent windings 16 may adapt to a smaller vessel diameter.

FIGS. 3A-3E illustrate a variety of different configurations of thefilament 12 terminal end 18. Terminal end 18 may be shaped into a numberof different configurations in order to provide an atraumatic end andreduce or minimize penetration of a lumen wall during use of theplatform 10. FIG. 3A is a section view of the filament 12 having a flatterminal end 18. FIG. 3B is a section view of the filament 12 having arounded terminal end 18 of about the same diameter as the overallfilament 12 diameter. FIG. 3C is a section view of the filament 12having an enlarged rounded or bulbous terminal end 18. The terminal end18 of FIG. 3C is has a dimension or a diameter that is larger thanoverall diameter or dimension of the filament 12. FIG. 3D is a sectionview of a filament 12 having a flat terminal end 18 and a ball or bulb21 mounted onto the terminal end 18. The filament 12 illustrated in FIG.3D accomplishes an atraumatic end through the use of the rounded ball orball 21. FIG. 3E is a section view of a filament 12 having a bent backdistal portion so that the terminal end 18 is rolled back into a roundedtip.

FIGS. 4A and 4B illustrate various different embodiments of a platform10. FIG. 4A illustrates a platform 10 having windings 16 with a diameterD2 and adjacent spacing 6 of S2. In contrast, FIG. 4B illustrates aplatform 10 embodiment where the filament 12 has a smaller overall shapeand the diameter D3 of the windings is much smaller than the diameter D2of FIG. 4A. In addition, the adjacent windings spacing 6 (S₃) is muchless than the adjacent windings spacing (S₂) shown in FIG. 4A. As willbe appreciated in the description that follows, FIGS. 4A and 4B are onlya few of the various different alternative embodiments of the platform10, a filament 12, a coil structure 14 and windings 16 of the variousembodiments of the present invention.

FIG. 5 is a perspective view of another embodiment of the platform 10.In this embodiment, the filament 12 as terminal end 18 having a roundedends as illustrated and described with regard to FIG. 3C or 3D. Inaddition the windings 16 have a variable diameter from the distal end 24to the proximal end 22. The diameter D2 at the proximal end 22 is largerthan the diameter D1 at the distal end 24. In general, the platform 10illustrated in FIG. 5 has a distal portion diameter of D1 that issmaller than a proximal portion diameter D2. Advantageously, the smallerdistal portion accommodates insertion into the fixed vein while thelarger proximal portion provides an adjustable opening used to attach tothe artery or other lumen.

The filament 12 may be provided for use in the platform 10 having avariety of different sizes, shapes and overall dimensions depending uponthe environment in which the platform device 10 will operate. FIGS.6A-6D illustrate a variety of different cross-section shapes of variousembodiments of the filament 12. FIG. 6A is a cross-section view of thefilament 12 having a circular or round shape. FIG. 6B is a cross-sectionview of the filament 12 having a generally rectangular shape. FIG. 6C isa cross-section view of the filament 12 having a rounded rectangularshape. FIG. 6D is a cross-section view of the filament 12 having across-section shape having a rounded portion and a flat portion. Afilament 12 may be extended into any of a variety of cross sectionshapes depending upon the design of the platform device 10 and theenvironment for use in an anastomosis formation.

It is to be appreciated that the orientation of the filament 12 used ina particular platform device 10 embodiment may be selected so that adesired filament orientation is obtained. In one aspect, a desiredfilament orientation is obtained when a particular shaped portion of afilament is positioned against a vessel wall. In another aspect, adesired filament orientation is obtained when a particular shapedportion of the filament is positioned so as to be exposed to the fluidflow within a vessel. The orientation, aspect or portion of the filamentalong with the shape, dimensions and properties may be adjusted asdescribed herein to provide a favorable environment for the successfulcompletion of an intended anastomosis. In one aspect, a filament 12 isselected so that when the associated platform device 10 is in use thefilament 12 is along the lumen wall. The filament has a profile in thefluid flow that minimizes or reduces adverse impact on fluid dynamicswithin the lumen. In this way, the filament and platform device aid instructurally supporting the lumen post-surgery while reducing the fluidflow in the lumen that after is an important factor in the anastomosisprocess. The flow of blood in anastomosis of blood vessels in aparticular example of this design consideration for platform device andfilament 12.

FIGS. 7A and 7B illustrate an embodiment of a platform device 10 formedfrom a filament 12 having a generally rectangular cross-section shape.In one aspect, the filament cross-section shape is as shown in FIG. 6B.In another aspect the filament cross-section shape is as shown in FIG.6C. In still other aspects, the width of the filament 12 is increasedand the height decreased from that illustrated in FIGS. 6B and 6C toform a filament with a form factor similar to a ribbon as illustrated inFIGS. 7A and 7B. FIG. 7A illustrates a platform 10 with a compact coilstructure 14 in a stowed configuration (L_(S)). The spacing 6 betweenadjacent windings 16 is small, optionally, when adjacent windings 16 arein contact. FIG. 7B illustrates a platform device 10 with increasedspacing 6 between adjacent windings 16 (S₁) as may occur in a deployedconfiguration. In the deployed configuration the coil structure 14 has alonger overall length (L_(Deployed)).

It is to be appreciated that one or more filaments 12 may be used toform an embodiment of a platform device 10 described herein. In oneaspect, two or more filaments are arranged closely together asillustrated in FIGS. 8A and 8B. A multiple filament configuration isalso referred to as a braided filament. Alternatively, as describedelsewhere herein, two filaments may be used to form a dual coil platformstructure (see platform 10 embodiments of FIGS. 10A-10C).

FIGS. 8A and 8B represent illustrative embodiments of a filament formedby 2, 3, 4 or more filament strands of biocompatible polymer. Thecombination of multiple smaller filaments or filament strands into asingle larger filament is also referred to as a braided filament. FIG.8A is a three filament strand braided filament for each of filamentstands A, B, C has a round cross section. FIG. 8B is a four filamentstrand braided filament. Each of filaments a, b, c, d has a round crosssection shape. The various shapes, sizes, properties and characteristicsof filaments (FIGS. 6A-6D) may be applied to the filament strands in abraided filament embodiment. The size and shape of each filament strandis selected such that the overall braided filament characteristics(size, shape, biodegradability and strength profile, etc.) is providedby the aggregate properties of the individual filament strands.

FIGS. 9A-9D illustrate a partial section view of cross section filamentsof three adjacent windings of the platform device. It is to beappreciated from these views how the overall filament size and shape maybe used to adjust the amount of contact between the filament used in aplatform and the adjacent luminal wall. While enlarged to show detail,it is to be appreciated that the overall dimension of a filament used ina platform is selected to have a size and shape so that the filamentpresents as low a profile as possible to the lumen interior and theintraluminal flow dynamic environment.

While each illustrative embodiment shows the filament just in oppositionwith the wall without luminal wall distension—other configurations arepossible depending upon the clinical and the anatomical circumstances ofa particular anastomosis. The characteristics of a filament and theformation of a platform device may be adjusted to provide variousdegrees of opposition to or forces against a lumen wall up to andincluding mild to moderate distention of the lumen wall by contact withthe filament/platform.

FIG. 9A illustrates the contact point of a filament 12 having a roundedcross-section shape as shown in FIG. 6A.

FIG. 9B illustrates at a section view of a multilayered biocompatiblepolymer formed into a rounded filament. In one aspect, properties ofeach filament layer may be adjusted to provide for the overallproperties of the layered filament structure. For example, the layerportion adjacent to the wall may be adapted for easy absorption into theluminal wall. Similarly, one or more of the outer layers may be adjustedaccording to the flow properties and anatomical requirements with andthe lumen or anastomosis location where the platform and filament willbe used. Still further, and other alternative embodiments, the interiorlayers may have copolymer properties adjusted to provide for the overallstrength and durability of the multilayer filament structure.

FIG. 9C illustrates a generally rectangular cross-section filament inposition against the lumen wall. The rectangular cross-section shapeillustrated in FIG. 9C may be, for example, as shown in FIGS. 6B, 6C orfor as a filament 12 configured as shown in FIGS. 7A, 7B.

FIG. 9D illustrates a braided filament 12 in position against theluminal wall. The braided filament illustrated is similar to theconfigurations described above with regard to FIGS. 8A and 8B.

Similar to the braided filament structures described above, FIGS. 10A,10B and 10C illustrate additional multi-filament platforms 10. FIG. 10Ais a side view of a platform 10 formed by a single filament looped backon itself or from a pair of filaments. The illustrated platform 10includes a pair of coiled structures 14 a, 14 b including a plurality ofwindings 16 a, 16 b. The terminal ends 18 are used to form knots orloops 44 to both fasten the filaments together at the proximal anddistal ends as well as to provide proximal and distal openings for theplatform 10. The surgeon may manipulate or adjust the filaments 12and/or knots 44 in the double coil embodiment using standard surgicalknot tying techniques to modify the platform according to the particularneeds of an anastomosis site.

The dual coiled platform embodiment of FIG. 10A has a proximal end 22and a distal end 24. In this illustrative embodiment, the proximal end22 has two knots 44 formed in the filament. The distal end 24 has a loopand a single knot 44. One or more of the knots 44 may be a slip knot.Optionally, the proximal and/or distal ends of the device may havefilaments formed into lassos to permit easy side/shape adjustments.

In some embodiments, the filaments 12 used to form a dual filamentplatform 10 may be about the same shape and size or may have differentshapes, sizes and properties. Moreover, the windings 16 a, 16 b and coilstructures 14 a, 14 b formed by each of the filaments may be doneindependent of the windings and coil structure of the other filament.Still further, in various other alternative embodiments, 3, 4 or moreindividual filaments 12 may be used to form multiple coil embodiments ofthe platform 10. Additionally or alternatively, the two or morefilaments 12 used in a double or multiple coil platform 10 may includesingle filament coils as well as braided filament coils (i.e., FIGS. 8A,8B).

FIGS. 10B and 10C illustrate two alternative portions of double coilplatform embodiments. The proximal end distal ends and associated knotsare not shown. FIG. 10 B illustrates a double coil platform embodimentwhere the first filament (fa) and the second filament (fb) used to makeeach of the coils 14 a, 14 b has about the same shape and size. However,the first filament (fa) forms a winding 16 a with a width W_(14a) thatis smaller than the winding 166 formed by the second filament (fb)having a width W_(14a). FIG. 10B also illustrates how the spacing 6between adjacent windings is about the same providing coil structures 14a, 14 b having approximately the same overall length.

FIG. 10C is a side view of another embodiment of a dual coil structureplatform 10. In this embodiment, the overall size of each filament 12 isdifferent (i.e., one filament is larger than the other heref_(b)>f_(a)). In addition, each of the coil structures 14 a, 14 b formedby each of the filaments f_(a), f_(b) has different sized windings 16 a,16 b. In the illustrative embodiment, filament a is larger than filamentb. In addition, the windings formed by filament a are spaced to becloser to one of the adjacent windings of filament b in contrast to thenearly even spacing of the various windings in the embodiment of FIG.10B.

With regard to the two filament platform embodiments of FIGS. 10A, 10Band 10C, various different configurations are possible, such as, forexample, forming each of the two filaments into similarly sized andshaped spiral forms. In one aspect, filaments are shaped into platformshaving the form of parallel or nearly parallel spirals. As seen best inFIG. 10A (and omitted from FIGS. 10B and 10C), the distal portion of oneor both filament will end with a slip knot loop that will end thatportion of the platform. The other filament will be attached to thatslip knot loop and will form at the opposite end of the platform anadditional slip knot loop. To this slip knot loop, the other filamentwill be attached. The diameter of the platform can vary as the spiralforms (i.e., coil structures 14 and windings 16) of the device can bemanipulated before or after implantation into a lumen or formation of ananastomosis. In addition, the length of the platform can also beadjusted by “stretching” or expanding or compressing the spiralstructure (i.e., windings or coil structure) in order to have theplatform cover a desired length of a lumen or anastomosis site. In stillother aspects, the terminal end or a proximal or distal portion adjacentto a filament terminal end may be cut off, formed into an additional ora replacement slip knot. In still other embodiments the end of theplatform or filament may be cut off and a new slip knot formed on theremaining filaments. In still further aspects, a filament may be joinedto another filament by using one or more clips made of a resorbablematerial having properties suited to the anastomosis proceduresdescribed herein (e.g., beginning of degradation, rate of degradationand timing to complete degradation).

In one aspect, an embodiment of a platform may be placed on a deliverydevice to facilitate positioning of the platform within a lumen to beused in an anastomosis. Additionally, the size and cross section shapeof the filament may be adjusted to provide a shape or size particular toa portion of the anastomosis site or lumen environment. For example,proximal or distal ends may be relatively larger to provide structuralsupport. In still other embodiments, the filament may be reduced in sizeto permit greater flexibility such as to form a desired curvature of alumen in an anastomosis. FIGS. 11A through 11D illustrate variousdifferent filament embodiments of an exemplary platform 10 loaded ontoan illustrative obdurator 35. The obdurator 35 has a constant diameteralong its length in these embodiments.

In the illustrative embodiment of a FIG. 11A, the filament 12 has adifferent diameter along the length of the platform. The filament 12 hasa diameter D1 on the proximal and distal portions and a smaller diameterD2 positioned between them.

In still other filament variations, the filament 12 may have a differentshape in different portions of a platform 10. FIG. 11B shows a platform10 loaded onto an obdurator 35 where the filament in the distal portionhas a diameter D1 and a rounded cross-section shape and a roundedcross-section shape and smaller diameter D2 in the proximal portion.Separating the proximal and distal portions is a filament 12 having aflat or oval cross-section shape having a width W1.

Still another filament variation is illustrated in FIG. 11C. In thisillustrative embodiment of a platform 10, the filament 12 in the distalportion has a flat or oval cross-section shape and a width W1, thefilament in the mid-portion has a rounded cross-section shape and adiameter of D1, and a proximal portion has a filament 12 with a roundcross-section shape and a diameter D2. In one aspect, the diameter D2 islarger than the diameter D1.

Additionally or alternatively, the filament 12 may have the same,different, or a variety of different spacings between adjacent windingsalong the length of the coil structure 14. It is to be appreciated thatreducing the spacing between windings will increase the amount offilament/length if platform thereby introducing more material/platforminto the lumen. Additionally, reduced spacing upon loading and deliveryprovides more flexibility for a surgeon to adjust the windings/coilstructure to accommodate the anatomical circumstances (i.e., see coilvariations in FIG. 20).

FIG. 11D illustrates a platform 10 on an obdurator 35 where the filament12 is formed into windings 16 at the distal end having a spacing S1. Thewindings 16 and the middle portion of the platform 10 of FIG. 11D have aspacing of S2. The windings 16 in the proximal portion of the platform10 in FIG. 11D are illustrated with a spacing S3. In this illustrativeembodiment, the spacing S3 is larger than the spacing S2 which is inturn larger than the spacing S1. In this embodiment, the filament 12used has the same size and shape but the spacing between the adjacentwindings is various. For example, more coils near the distal end or alonger length of a coil structure with less material in the mid regionand still less material in the proximal region may be desirous forcertain anatomical locations.

Still other filament variables and embodiments are possible beyond thosewhich are illustrated herein. Different shapes or sizes of the filamentor the platform properties may be selected based on lumen properties orchallenges of a particular anastomosis site. Size, shape of filament andspacing of filament windings and number of windings per unit length maybe each adjusted alone or in numerous combinations to adjust the overallplatform properties with respect to the lumen, anastomosis location orother factors. As a result, embodiments of the platform device may beadapted and configured whereby the length from the platform proximalportion to the distal portion is from about 2 cm, 3 cm, 4 cm, 5 cm, 6cm, 7 cm, 8 cm, 9 cm, 10 cm, 11 cm or 12 cm before implantation into alumen. Still further, owing to the nature of the windings and coil bodyadjustment and overall platform device manipulation, embodiments of theplatform device may be adapted and configured whereby the length fromthe platform proximal portion to the distal portion is from about 2 cm,3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 11 cm or 12 cm afterimplantation into a lumen.

In still further embodiments, variations in size and shape may occuralong the length of a single filament. The location of these filamentcharacteristic variations may be specifically selected so that aparticular size, shape, or orientation of shape of a filament is locatedin a particular portion of a lumen or anatomical site according to thespecific anastomosis situation presented. Variation in filamentproperties permits differences in size, shape, spacing along the distal,middle or proximal portions of a platform embodiment to correspond tothe various, specific anastomosis requirements depending upon the needsof a particular anatomical, clinical or physiological challengepresented for the platform use envisioned.

FIGS. 12A and 12B are top and side views respectively of an obdurator 35having a mating feature 37 in a distal portion. The mating feature 37 isin one illustrative embodiment a cavity shaped to releasably engage thedistal end of a filament and thereby secure the platform to theobdurator 35. Additionally, use of the mating feature 37 permits theobdurator to impart rotation to the platform disposed thereon tofacilitate insertion into a platform lumen for use in an anastomosis(see FIG. 12D).

FIG. 12C is a side view of the abdurator of FIGS. 12A, 12B with aplatform 10 loaded onto the obdurator 35. The platform distal portion 24is loaded onto the distal portion of the abdurator. In this illustrativeembodiment, the terminal end 18 of the filament 12 includes a feature 38having a complementary and mating shape or size to facilitate couplingto mating feature 37. FIG. 12D is a side view of the embodiment of FIG.12C inserted into a vein 31. As indicated by the arrow, the obdurator 35is rotated so as to encourage the advancement of the obdurator andplatform into the vein 31. Also visible in the view of FIG. 12D is theengagement of the complementary mating feature 38 with the feature 37.

While the obdurator 35 may have a constant diameter along its length,other configurations are possible. Optionally, the profile of theabdurator may be selected to aid in shaping the lumen carrying theplatform device 10. FIG. 12E is a cross-section view of an obdurator 35having a generally increasing diameter from the distal end to theproximal end. In the illustrated embodiment, diameter D0 is the smallestwith increasing diameter sizes from D₁ to an increasing D2 to thelargest diameter D3. A platform 10 formed from a constant diameterfilament 12 is shown in position along the distal portion of theobdurator 35 in FIG. 12E.

In addition or alternatively, an obdurator 35 may have a proximalportion with the first diameter D1 that is larger than the distalportion having a second diameter D2. In the illustrated embodiment ofFIG. 13 the difference in the diameter D1 and D2 is selected toaccommodate the platform 10. As shown in the existing embodiment, afilament having a diameter F_(D) is loaded onto the D2 sized portion ofthe obdurator 35. As a result, the overall diameter of the obdurator isnearly equal along its length as it is loaded within the sheath 40.

FIG. 14 is a section view of a different embodiment of a platform deviceloaded onto an obdurator within an introducer sheath 40. In thisillustrative embodiment, the obdurator has a constant diameter. Incontrast to the introducer sheath embodiment illustrated in FIG. 13, theintroducer sheath 40 illustrated in FIG. 14 may extend beyond the distalmost windings 16 of the distal platform device portion 24. Thisconfiguration of the introducer sheath 40 provides a tapered tip to thesheathed obdurator 35 embodiment shown in FIG. 14.

In one illustrative embodiment, the properties of the filament 12 andstructure of the platform device 10 are specifically selected so as toprovide a conducive environment to the formation of an anastomosis. Ingeneral, a platform 10 will provide the necessary shape, orientation,and alignment between a platform lumen and a second lumen use to formthe anastomosis. In particular, the biodegradable aspects of thefilament and the overall characteristics of the platform are tailored toprovide initial, postsurgical structure that gives way over time in acontrolled fashion as the vessels of the anastomosis heal and adapt toappropriate sizes and strength.

FIGS. 15A-15D illustrate, respectively, the initial platform condition(FIG. 15A) and degraded condition during absorption (FIGS. 15B, 15C)until completely absorbed (FIG. 15D). FIGS. 15A through 15D provide oneexemplary platform degradation profile for an exemplary anastomosis. Theplatform proximal end 22 provides the shape and opening of the vein toattach to the anastomosis site.

FIG. 15A platform 10 is shown along the vein 31 adjacent to ananastomosis 34 formed with artery 32. Other profiles are possible suchas total absorption of a platform after week but within 2-3 weeks or atabout 3 weeks or less than 4 weeks from implantation. Initially, theplatform 10 is structurally intact and is supporting the angle 36 of thevein 31 used to form the anastomosis 34. FIG. 15B illustrates thesituation in the anastomosis and the platform after approximately oneweek. About one week after surgery, the platform 10 begins to degrade.The vein and the artery are growing as a consequence of increased bloodflow provided by the additional support of the platform during thepostsurgical period. The degradation and corresponding loss ofstrength/support of the platform to the surrounding lumen is selected tocorrespond to the increasing strength and potency of the lumen.

FIG. 15C is the platform supported anastomosis approximately three weekspost-surgery. The platform 10 has continued to degrade in theintervening weeks. In one illustrative embodiment, the properties of thefilament 12 and the overall design of the platform device 10 wouldresult in a platform 10 that has substantially completely dissolved bythis postsurgical stage. Alternatively, in a different anastomosissituation, portions of the platform may remain and continue to providesome level of support although less than provided in prior weeks. Bythis stage, there is significant increase in vein and artery diameterand increasing vein wall thickness.

FIG. 15D is the platform supported anastomosis region five weeks afterthe surgery. In this illustrative embodiment, the platform 10 iscompletely removed (i.e., absorbed or biodegraded) from the surgicalsite. In one aspect, the illustrative anastomosis 34 is an arteriovenousfistula and it will have reached full maturation by this stage.

FIGS. 16A through 16G provide an illustrative surgical procedure for theuse of a platform based anastomosis formation. In the exemplaryprocedure that follows, the anastomosis is an arteriovenous fistula andthe principals and techniques may be applied to other surgical sites andconditions. First, as shown in FIG. 16A, dissect the artery 32 and vein31 involved in the procedure. Next, as shown in FIG. 16B, ligate thedistal part of the vein 94 and clamp 92 the proximal portion of vein 31and perform a venotomy. Next, as shown in FIG. 16B bring the now mobilevein to the site 52 of the future anastomosis on the artery. Measure andevaluate the overall length of the mobile vein and the selected site onthe artery for the position of the anastomosis. The desired anastomosisangle 36 is also verified in the step. Thereafter, as illustrated inFIG. 16D, load a platform 10 into the mobile vein 31 m by inserting theplatform into the proximal opening of the vein. Next, as in FIG. 16E,provide clamps to the artery and perform the arterial incision 53 at thesite 52 of the future anastomosis. Next, as in FIG. 16F, position theproximal opening of the mobile vein or the platform lumen into contactwith the arterial incision 53. The procedure concludes by suturing 82the open proximal end of the vein to the arterial incision site 52.

The platform 10 within the vein 31 may be adjusted to provide thedesired orientation, shape, or angle 36 between the vein 31 and theartery 32 at the anastomosis site 34. In this specific embodiment, theplatform 10 will be adjusted so that the vein forms a desired angle andorientation to facilitate full arteriovenous fistula maturation withinthe desired time frame. Advantageously, the properties of the filament12 permit the overall platform 10 to be adjusted by the surgeon duringthe procedure by manual manipulation of the platform. In order toprovide a desired anastomosis position, the surgeon may manipulate theplatform by altering the size of one or more windings or adjusting thespacing between one or more windings or altering the overall curvatureof the platform within the vein. Advantageously, the number and spacingof the windings in the platform device provide a wide range of shapesand curves to accommodate a variety of different anatomical situations.

In still further aspects, a platform device 10 may be adjusted during orafter the anastomosis procedure in order to provide or facilitateformation of the desired angle of the anastomosis site. FIG. 16illustrates an embodiment of the platform illustrated in FIG. 12C inposition within an anastomosis site. The surgeon may by using experienceand observations or through the use of a template for measuring device,manipulate the platform 12 within the vein in order to provide thedesired radius of curvature of the vein adjacent to the anastomosis site(i.e., at the junction between the vein and the artery). The overallcurvature 23 of the vein may be described as having an inner radius ofcurvature r1 and an outer radius of curvature r2. In one aspect, thespacing between adjacent windings on the inner radius are shortened toprovide adjustments to the inner radius of curvature. Optionally,spacing between windings of the platform along the outer radius ofcurvature may be increased to adjust the outer radius of curvature r2.

FIG. 16G also illustrates the distal platform portion 24 inserted intovein 31 into the fixes vein portion 31 f (beyond the dissected or mobilevein 31 m). In this way, the platform device extends between the fixedvein portion 31 f at the distal end and the sutured anastomosisconnection at the artery on the proximal end. In this way, the platformdevice is a flexible element between two fixed points that may then beused to adjust the shape of the lumen between the points.

FIG. 17 is a flowchart of an exemplary platform based anastomosisformation procedure 1700. Various aspects of the illustrative surgicalprocedure will be described with reference to FIGS. 18A through 18G.First, at step 1705, evaluate lumen characteristics for anastomosis. Asshown in FIG. 18A1 the platform lumen and the second lumen are evaluatedfor their relative positions as well as general size and shape alongwith the desired characteristics, orientation, size, shape and otherfactors for the anastomosis. Also shown in the view of FIG. 18A1 is theidentification of the site 52 of the planned anastomosis and the secondlumen 32. The platform lumen 31 is dissected along a length to provide amobile portion 31 m and a fixed portion 31 f. The length of the mobileportion 31 m and the relative position of the fixed portion are selectedaccording to the desired anastomosis angle and the site of the plannedanastomosis indicated in the second lumen.

Next, step 1710, load the delivery device with platform of appropriatedimensions and characteristics. FIG. 18A2 illustrates a platform 10positioned along an obdurator 35 within an introducer sheath 40. Theproperties of the platform 10 including the filament characteristics,dimensions, polymer composition and other factors have been selectedbased upon the desired strength and degradation curves among otherfactors for the intended anastomosis formation. Next, step 1715, preparethe lumens for anastomosis. As shown in FIG. 18A1 and as previouslydescribed, some portion of the open procedure, ligation, or dissectionof one or both of the involved lumens it may have occurred. If not bythis point in the procedure, the lumens are prepared for anastomosis.

Next, at step 1720, insert the delivery device into the free end of theplatform lumen. Step 1720 is illustrated in FIG. 18B. FIG. 18Billustrates the insertion of the distal portion of the introducer sheathinto the open proximal end of the platform lumen. The introducer sheathis advanced distally along the platform lumen until the desired positionof the distal portion of the platform is reached. In one aspect, thedistal most portion of the platform will be positioned beyond theinterface between the mobile platform lumen and the fixed platformlumen. In another aspect, the distal most portion of the platform willbe positioned within the platform lumen at or proximal to the transitionbetween the mobile platform lumen and the fixed platform lumen. In stillanother aspect, the introducer sheath is advanced into the platformlumen until a sufficient amount of the platform for the desiredanastomosis characteristics is positioned within the platform lumen.

The next step of the platform based anastomosis procedure 1700 is todeploy the platform within the platform lumen. (Step 1725). This step isillustrated through the sequence of FIGS. 18C, 18D, 18E, and 18F. FIG.18C illustrates a section view of a distal portion of the platform afterthe introducer sheath 40 has been withdrawn proximally to expose severalof the distal most windings of the platform 10. The windings of 16 thatare no longer held by the introducer sheath 40 have now expanded into alarger diameter and engaged with and opened the platform lumen. It is tobe appreciated that the degree of spring back or expansion force in aplatform device or filament may be adjusted depending upon thecharacteristics of the anastomosis is being formed.

FIG. 18D is an end view of the expansion of the windings 16 illustratedin FIG. 18C. A portion of the windings 16 distal to the introducersheath 40 is shown engaging with the interior wall of the lumen. Alsoshown is a more proximal portion of the platform where the windings 16are still engaged with the introducer sheath 40. This view illustrateshow the sheath is used to combine the loaded platform during insertioninto the platform lumen. The platform 10 continues to be deployed in thesame action by holding the obdurator 35 in position within the platformlumen while withdrawing the introducer sheath 40. Finally, asillustrated in FIG. 18D, the platform 10 is completely or substantiallycompletely within the platform lumen, depending upon the requirements ofthe specified anastomosis. Additionally, the obdurator and theintroducer sheath are clear of the platform lumen at the conclusion ofthis step. FIG. 18F illustrates a platform lumen with a platform device10 deployed within it and prepared for attachment to the second lumen.In the illustrative embodiment of FIG. 18F, the platform 10 has beenadvanced within the platform lumen so that the distal most portion ofthe platform has a number of windings 16 within the platform lumen andbeyond the demarcation point between the mobile lumen and the fixedlumen. The length of the platform 10 inserted beyond the demarcationbetween the mobile and fixed lumen varies depending upon therequirements of the particular anastomosis. In one embodiment, thedistal most portion of the platform 10 extends on about 1 cm, 2 cm, 3cm, or 4 cm beyond the demarcation between the mobile lumen and thefixed lumen.

Once the platform 10 is positioned within the mobile lumen, the nextstep of the anastomosis procedure 1700 is to couple the proximal end ofthe platform lumen to an anastomosis site on the second lumen. (Step1730). FIG. 18G illustrates one embodiment of a platform lumen attachedto a second lumen. The lumen may be attached by suture, staple, or othersuitable fixation device or technique suited to the anastomosis.

In this illustrative embodiment, the platform lumen is extended andsupported by the platform between the two fixed points of the portion ofthe platform beyond the fixed mobile transition and the anastomosis siteon the other lumen. In this way, the platform lumen behaves as a bowstringed between these two fixed points and may thereafter be adjustedaccordingly. Additionally, positioning a platform of sufficient lengthso that it extends between the anastomosis point and into the fixedplatform lumen portion is useful for preventing kinking of the platformlumen. Finally, at step 1735, as needed, shape the platform within theplatform lumen to adjust the anastomosis as desired to achieve thedesired anastomosis characteristics (i.e., see FIG. 2D). In one aspect,the platform is shaped by manual manipulation of the filament within theplatform lumen to adjust the properties of the platform (spacing betweenwindings, coil size, filament orientation, or other factors) as neededto provide the desired anastomosis environment, angle or shape of alumen.

In other additional alternative embodiments, the various platformconfigurations described herein may be used in any of a wide range ofsurgical procedures where an opening in a vessel is to be maintainedduring the procedure or for a period thereafter. In one alternative usesituation, embodiments of the platform described herein are used tofacilitate the reconnection of the vasculature are to a transplantorgan. FIG. 19 illustrates a top view of a transplant organ (o) havingvascular lumens a-d (La-Ld). Just prior to the initiation of therevascularization during the transplant procedure, the new vasculatureare provided by vessels Va-Vd have been provided with appropriatelysized and configured platforms Pa-Pd. In addition, FIG. 19 alsoillustrates the use of appropriately sized and characterized platformsP1 and P2 for use in the organ lumens La and Lb. Platforms P₁ and P₂ maybe sized and shaped to provide an appropriate mechanical assistance toensure the opening and orientation of La and Lb is maintained. The useof platforms as described herein and as illustrated in the configurationof FIG. 19 provide for mechanical opening of the vessels involved in atransplant procedure. It is believed that the use of platformsconfigured as described in herein would permit the attachment oftransplant vascular sure to proceed more quickly because the platformswithin the vessels keep the vessel open particularly at the proximalmost opening for easy attachment to the organ vasculature. Optionally oradditionally, the length of the platform disposed within thevascularization lumen also provides the ability to adjust theanastomosis characteristics of each of the vessels that are attached tothe transplant organ. Accordingly, FIG. 19 illustrates various differentangulation (Pc, Pd and Pa) or straight (Pb) lumen positions just priorto initiation of the vascular attachment procedure.

FIG. 20 illustrates an end view of a representative obdurator withvarious diameters of platform windings. It is to be appreciated that thevarious alternative embodiments, configurations, and characteristics ofthe filament 12 and the platform device 10 including the resulting coilstructures 14 and windings 16 may be manipulated into a wide variety ofstructures including different response factors when deployed inside ofa lumen. The resulting expansion of the windings 16 of the platformreleased from an introducer sheath as illustrated and described abovewith regard to FIGS. 18C and 18D is only one example of a property ofthe platform 10. By selecting the characteristics and polymer propertiesof the filament 12 and the associated geometry and configuration of theplatform device 10 the deployment of the platform when released within alumen may be adjusted. The variation of the platform device deploymentis illustrated in the view of FIG. 20. In one embodiment the platform 10may be configured to release from the obdurator to a representativediameter D1 that is larger than the obdurator diameter but yet smallerthan the lumen diameter. In still another aspect, the platform 10 may beconfigured for release from the obdurator to expand to a diameter thatis the same or nearly the same as the diameter of the vessel where theplatform will be used. In still another aspect, the platform 10 may beconfigured for release from the obdurator to expand to a diameter thatis larger than the diameter of the vessel where the platform will beused. In this last aspect, the platform may be oversized to the degreeneeded for the formation of the vessel into a desired anastomosis site.Is to be appreciated that the various different expansion propertiesillustrated and described with regard to FIG. 20 may be the same alongthe entire length of the platform. In still another alternative aspect,the expansive properties of one portion of the platform may expand moreor less than an adjacent portion. In one specific aspect, a distalportion of a platform may expand to be undersized (d1) within the lumenwhile a more proximal portion of the same platform may be sized todeploy into the lumen into a diameter that is about the same size as thelumen (d2) or larger (d3) so as to distend the lumen.

In addition to the exemplary uses described herein, alternativeembodiments and configurations of the platform device and involvedfilament or filaments may be selected, sized and configured for use insystems/lumens/locations/procedures within a human or animal body.Accordingly, the filament properties and platform configuration may beadapted for use in for example, in the biliary tract, within the lungs,within the guide, within the lymphatic system, within the urinarysystem, or within any of the lumens of the male or female reproductivesystem. In still other aspects, embodiments of the biocompatiblefilament and related platform devices may be adapted for use in bloodvessels after performing an intravascular procedure. In one exemplaryembodiment, the filament and platform is selected for use in a vesselafter performance of an atherectomy.

In various different alternative embodiments, an anti-proliferativecomposition is formulated so as to be provided with the platform such asin the form of a coating on, within, along or provided by a filament, oris released by or within a portion of a multiple layer filament (seeFIG. 9B) or a portion of a surface of a particular face of a filament(e.g., flat portion of filament in FIG. 6D) or provided by one or moreof the filament strands of a braided filament. Exemplaryanti-proliferative compositions include anti-proliferative drugs(generic name followed by trademark in parentheses):

Terazosin—(Hytrin) Antihypertensive, Benign prostatic hyperplasiatherapy agent

Finasteride (Systemic)—(Propecia, Proscar) Benign prostatic hyperplasiatherapy agent; hair growth stimulant, alopecia androgenetica (systemic)

Doxazosin (Systemic)—(Cardura) Antihypertensive, Benign prostatichyperplasia therapy agent

Tamsulosin (Systemic)—(Flomax) Benign prostatic hypertrophy therapyagent

Prazosin (Systemic)—(Minipress) Antidote, to ergot alkaloid poisoning,Antihypertensive, Benign prostatic hyperplasia therapy agent,Vasodilator, congestive heart failure, Vasospastic therapy adjunct

More examples of anti-proliferative drugs, include for example (genericname followed by trademark name in parentheses): Mitomycin for injection(Mutamycin); bleomycin sulfate for injection (Blenoxane); doxorubicinhydrochloride for injection (Adriamycin or Rubex or Doxorubicinhydrochloride); daunorubicin HCl (Cerubidine); dactinomycin forinjection (Cosmegen); daunorubicin citrate (liposome) for injection(DaunoXome); doxorubicin HCl (liposome) for injection (Doxil),epirubicin hydrochloride for injection (Ellence); idarubicinhydrochloride for injection (Idamycin); plicamycin (Mithracin);pentostatin for injection (Nipent); mitoxantrone for injection(Novantrone); and valrubicin (Valstar).

In various different alternative embodiments, an anti-thromboticcomposition is formulated so as to be provided with the platform such asin the form of a coating on, within, along or provided by a filament, oris released by or within a portion of a multiple layer filament (seeFIG. 9B) or a portion of a surface of a particular face of a filament(e.g., flat portion of filament in FIG. 6D) or provided by one or moreof the filament strands of a braided filament. Exemplary anti-thromboticcompositions include anti-thrombotic drugs (Generic Names):

Anisindione Indications: Embolism, pulmonary; Embolism, pulmonary,prophylaxis; Thrombosis; Thrombosis, prevention

Antithrombin III (Human) Indications: Embolism; Thrombosis

Argatroban Indications: Thrombosis; Thrombocytopenia, secondary toheparin

Dicumarol Indications: Embolism, pulmonary; Embolism, pulmonary,prevention;

Fibrillation, atrial, adjunct; Occlusion, coronary, adjunct; Thrombosis;Thrombosis, prevention

Heparin Sodium Indications: Coagulopathy, consumption; Dialysis,adjunct; Embolism, pulmonary; Embolism, pulmonary, prevention;Fibrillation, atrial, adjunct; Surgery, adjunct; Thrombosis; Thrombosis,prevention; Transfusion, adjunct

Lepirudin (rDNA) Indications: Thrombocytopenia, secondary to heparin;Thrombosis tPA, Reteplase (generic for Retavase®), Urokinase.

In various different alternative embodiments, an anti-inflammatorycomposition is formulated so as to be provided with the platform such asin the form of a coating on, within, along or provided by a filament, oris released by or within a portion of a multiple layer filament (seeFIG. 9B) or a portion of a surface of a particular face of a filament(e.g., flat portion of filament in FIG. 6D) or provided by one or moreof the filament strands of a braided filament. Exemplaryanti-inflammatory compositions include anti-inflammatory drugs:

Aspirin or Acetyl Salicylic Acid

Oral Corticosteroids (generic name followed by trademark inparentheses)—Prednisone

(Deltasone), methylprenisolone (Medrol), prednisolone solution(Pediapred, Prelone)

Inhaled Corticosteroids (generic name followed by trademark inparentheses)—Flunisolide (AeroBid, AeroBid-M), triamcinolone (Azmacort),beclomethasone (Beclovent, Vanceril), budesonide (Pulmicort),fluticasone (Flovent), Nedocromil sodium (Tilade), Cromolyn sodium(Intal)

Nonsteroidal Anti-Inflamatory Agents (Generic Names):

1. Diclofenac

2. Diflunisal

3. Etodolac

4. Fenoprofen

5. Floctafenine

6. Flurbiprofen

7. Ibuprofen

8. Indomethacin

9. Ketoprofen

10. Meclofenamate

11. Mefenamic Acid

12. Meloxicam

13. Nabumetone

14. Naproxen

15. Oxaprozin

16. Phenylbutazone

17. Piroxicam

18. Rofecoxib

19. Sulindac

20. Tenoxicam

21. Tiaprofenic Acid

22. Tolmetin

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, as used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements, these features/elements should not be limitedby these terms, unless the context indicates otherwise. These terms maybe used to distinguish one feature/element from another feature/element.Thus, a first feature/element discussed below could be termed a secondfeature/element, and similarly, a second feature/element discussed belowcould be termed a first feature/element without departing from theteachings of the present invention.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately,” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical rangerecited herein is intended to include all sub-ranges subsumed therein.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept, if more than one is, in fact, disclosed. Thus, althoughspecific embodiments have been illustrated and described herein, anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

What is claimed is:
 1. A platform device, comprising: a bioabsorbablefilament selected to begin degrading within one week of implantationinto a lumen of a human or animal body and to be substantiallycompletely absorbed by the animal or human body after an anastomosisassistance period has elapsed; a coil structure having a length along amajor axis and a width along a minor axis formed by a plurality ofwindings of the filament about the major axis wherein the filament widthand the spacing between the windings relates to the coil structurelength and the dimension of the windings across the minor axis relatesto the coil structure width; and an obdurator having a distal end, aproximal end, and an overall shape adapted to receive the plurality ofwindings, the obdurator having a tip on the distal end and an increasingdiameter of the overall shape towards the proximal end, wherein theplurality of windings are wound around the tip so that the plurality ofwindings have increasing winding diameters towards the proximal end. 2.The platform device of claim 1 wherein the anastomosis assistance periodis less than three weeks.
 3. The platform device of claim 1 wherein theanastomosis assistance period is less than five weeks.
 4. The platformdevice of claim 1 wherein when the coil structure is in a deployedconfiguration the coil structure forms a selected anastomosis anglehaving an inner radius of curvature and an outer radius of curvaturewherein the spacing between adjacent windings along the inner radius ofcurvature is less than the spacing between adjacent windings along theouter radius of curvature.
 5. The platform device of claim 1 wherein adistal aperture of the platform device is formed into a shape selectedbased on a dimension or a shape of another lumen at an anastomosis site.6. The platform device of claim 1 wherein the bioabsorbable filament isa biocompatible polymer selected from the group consisting of: a(poly)lactic acid, a poly(lactic-co-glycolic acid), a polyglycolide, acopolymer, and a cross-linked polymer.
 7. The platform device of claim 1wherein the bioabsorbable filament is a biocompatible polymer having anin vivo degradation rate corresponding to the anastomosis assistanceperiod that corresponds to the time required for fistula formation. 8.The platform device of claim 1 wherein when the platform device is in adeployed configuration a distal aperture of the platform device has oneor more windings of decreasing dimension across the minor axis.
 9. Theplatform device of claim 8 wherein the distal aperture has acircumference and a shape selected based on an anastomosis angle of theplatform device in use to form an arteriovenous fistula.
 10. Theplatform device of claim 1, the obdurator comprising a mating featureshaped to receive a corresponding mating feature formed on a distalportion of the filament.
 11. The platform device of claim 1 wherein theobdurator distal end diameter is smaller than the obdurator proximal enddiameter.
 12. The platform device of claim 1 further comprising anintroducer sheath having a lumen dimensioned to receive the filamentloaded onto the obdurator.
 13. The platform device of claim 1 where thelength from a platform proximal portion to a distal portion is fromabout 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 11 cm or 12cm before implantation into a lumen.
 14. A method for inserting aplatform device for use in creation of an arteriovenous fistula,comprising the steps of: providing a bioabsorbable filament selected tobegin degrading within one week of implantation into a lumen of a humanor animal body and to be substantially completely absorbed by the animalor human body after an anastomosis assistance period has elapsed;forming a coil structure having a length along a major axis and a widthalong a minor axis formed by a plurality of windings of the filamentabout the major axis wherein the filament width and the spacing betweenthe windings relates to the coil structure length and the dimension ofthe windings across the minor axis relates to the coil structure width;loading the coil structure onto an obdurator to form the platformdevice, the obdurator having a distal end, a proximal end, and anoverall shape adapted to receive the plurality of windings, theobdurator having a tip on the distal end and an increasing diameter ofthe overall shape towards the proximal end, wherein the plurality ofwindings are wound around the tip so that the plurality of windings haveincreasing winding diameters towards the proximal end; identifying acandidate artery and a candidate vein; dissecting the candidate vein;inserting the platform device into the candidate vein; creating a breachin the candidate artery at a desired angle and location; forming ananastomosis by attaching the candidate vein to the candidate artery; andmanipulating the platform device into a shape selected to minimizeturbulent blood flow in the anastomosis.